code: def test_unreachable_queue(monkeypatch):
      monkeypatch.setattr(queues, "HTTP_QUEUE_TOKEN", "test-token")
  
      test_queue = HTTPQueue("test_http_queue", STATE_UPDATE_TIMEOUT)
  
      resp1 = mock.MagicMock()
      resp1.status_code = 204
  
      resp2 = mock.MagicMock()
      resp2.status_code = 201
  
      test_queue.client = mock.MagicMock()
      test_queue.client.post = mock.Mock(
          side_effect=[resp1, resp1, resp2]
      )
  
      with pytest.raises(queue.Empty):
          test_queue._get()
  
      # Test backoff on queue.put
      test_queue.put("foo")
      assert test_queue.client.post.call_count == 3
  
imports: import base64
  import multiprocessing
  import pickle
  import queue
  import time
  from unittest import mock
  import pytest
  import requests_mock
  from lightning.app import LightningFlow
  from lightning.app.core import queues
  from lightning.app.core.constants import HTTP_QUEUE_URL, STATE_UPDATE_TIMEOUT
  from lightning.app.core.queues import READINESS_QUEUE_CONSTANT, BaseQueue, HTTPQueue, QueuingSystem, RateLimitedQueue, RedisQueue
  from lightning.app.utilities.imports import _is_redis_available
  from lightning.app.utilities.redis import check_if_redis_running
label_desc: Use image node_id 10 for calling a global function with example usage: test_unreachable_queue(monkeypatch) without return types